In the past, we have avoided using very coarse grained material in sinkhole prone areas as it also allows water to easily filter into the ground surface bringing with it Carbonic acid, which, over time will, cause the calcite in the dolimite rich soils to degrade. Usualy want to use something...
By far and large, adding concrete weight to the foundation is usualy the easier answer.
The only major issues come up if the soil is contaminated and over-excavation is discouraged. Also, if the bearing of the soil is relatively limited, and the new load will induce too much settlements, you...